Learn how to efficiently use XQuery to print specific keys from JSON data, breaking down the steps to achieve your desired results ...
To extract specific keys from JSON data using XQuery, you can use the json-to-xml function available in XQuery 3.1 and later. This allows you to convert JSON into an XML format, from which you can easily extract the desired keys.
Example JSON Data
Assuming you have the following JSON data:
{
"fruits": [
{"name": "Apple", "color": "Red"},
{"name": "Banana", "color": "Yellow"},
{"name": "Orange", "color": "Orange"}
],
"vegetables": [
{"name": "Carrot", "color": "Orange"},
{"name": "Broccoli", "color": "Green"}
]
}
Step 1: Convert JSON to XML
First, you need to convert the JSON data into XML format:
let $json := '{
"fruits": [
{"name": "Apple", "color": "Red"},
{"name": "Banana", "color": "Yellow"},
{"name": "Orange", "color": "Orange"}
],
"vegetables": [
{"name": "Carrot", "color": "Orange"},
{"name": "Broccoli", "color": "Green"}
]
}'
let $xml := json-to-xml($json)
Step 2: Extract Specific Keys
Now, you can extract specific keys from the converted XML. For example, to extract the names of all fruits:
return
<fruit-names>
{
for $fruit in $xml/fruits/item
return
<name>{ $fruit/name/text() }</name>
}
</fruit-names>
Full Example
Here’s the complete XQuery:
let $json := '{
"fruits": [
{"name": "Apple", "color": "Red"},
{"name": "Banana", "color": "Yellow"},
{"name": "Orange", "color": "Orange"}
],
"vegetables": [
{"name": "Carrot", "color": "Orange"},
{"name": "Broccoli", "color": "Green"}
]
}'
let $xml := json-to-xml($json)
return
<fruit-names>
{
for $fruit in $xml/fruits/item
return
<name>{ $fruit/name/text() }</name>
}
</fruit-names>
Explanation
- Convert JSON: The
json-to-xml function transforms the JSON string into XML.
- Loop Through Fruits: The
for loop iterates over each fruit item.
- Extract Names: The
<name> element is created for each fruit, containing the name extracted from the XML.
Conclusion
This method allows you to effectively extract specific keys from JSON data using XQuery by first converting it to XML, making it easy to navigate and retrieve the desired information.
